Detection and characterization of OXA-48-producing Klebsiella pneumoniae originated in Bulgaria

We report the identification of OXA-48-producing Klebsiella pneumoniae, causing peritonitis in a cancer patient admitted to the Oncology Hospital in Sofia. The isolate had reduced susceptibility to carbapenems but remained susceptible to extended-spectrum cephalosporins. PCR and sequencing confirmed the presence of bla_OXA-48 gene flanked by two intact copies of IS1999 on truncated ΔTn1999.1. This transposon was located on unusual non-typeable 29-kb plasmid that could be transferred only by transformation. Multilocus sequence typing (MLST) indicated the presence of the sequence type ST530.This is the first documented infection due to OXA-48-producing Enterobacteriaceae strain in Bulgaria.     

产ESBLs肺炎克雷伯菌ESBLs基因与可移动遗传元件相关性分析

目的 了解产超广谱β-内酰胺酶(extended spectrum beta-lactamases, ESBLs)肺炎克雷伯菌(Klebsiella pneumoniae, Kpn)ESBLs基因与可移动遗传元件(mobile genetic elements, MGEs)标记基因的携带情况及其相关性。方法 收集从住院患者标本中分离出的产与非产ESBLs Kpn非重复菌株各100株，采用PCR检测细菌中4种ESBLs基因与8种MGEs标记基因，并作指标聚类分析。结果 产ESBLs Kpn中，ESBLs基因阳性率高达100%；MGEs标记基因以IS26、ISEcp1、traA、trbC和intI1基因为主，阳性率高于非产ESBLs Kpn(P<0.05)；ESBLs基因与MGEs标记基因的同时检出率明显高于非产ESBLs Kpn (P<0.05)；基因blaSHV-12、blaOXA-1与MGEs基因tnpU、tnp513、merA、intI1相关联，基因blaTEM-1、blaCTX-M-125与MGEs基因ISEcp1、IS26、traA相关联。产与非产ESBLs Kpn均没有只检出MGEs标记基因的菌株。结论 产ESBLs Kpn ESBLs基因和MGEs标记基因携带率高，两者存在相关性，可能是产ESBLs Kpn出现多重耐药的重要原因；MGEs标记基因在Kpn中可能不是单独存在的。     

外周血CD4+CXCR5+Tfh水平对肺炎克雷伯菌感染者预后的影响

目的　检测肺炎克雷伯菌感染者外周血CD4+CXCR5+滤泡辅助性T细胞（T follicular helper cell, Tfh）水平，探讨其对患者预后的影响。方法　选取2017年7月—2019年5月于本院ICU住院治疗的147例患者为研究对象，根据患者入院后是否出现肺炎克雷伯菌感染，将其分为感染组（69例）和未感染组（78例）。采用流式细胞术检测147例患者外周血CD4+CXCR5+Tfh水平。采用单因素分析肺炎克雷伯菌感染的影响因素；采用单因素分析和多因素Logistic回归分析肺炎克雷伯菌感染者预后的影响因素。结果　感染组的住院时间、入住ICU时间、入住ICU时APACHE II评分、机械通气时间及心血管疾病、多器官功能障碍综合征、接受手术、恶性肿瘤患者比例均高于未感染组，差异均有统计学意义（P均＜0.05）。感染组外周血CD4+CXCR5+Tfh水平、死亡患者比例均高于未感染组（P均＜0.05）。感染组中死亡患者外周血CD4+CXCR5+Tfh水平高于生存患者（P＜0.05）。CD4+CXCR5+Tfh、碳青霉烯类耐药、入住ICU时APACHE II评分是影响肺炎克雷伯菌感染者死亡的独立危险因素（P均＜0.05）。结论　外周血CD4+CXCR5+Tfh水平在肺炎克雷伯菌感染者中显著升高，CD4+CXCR5+Tfh可能通过参与机体免疫应答影响感染者的预后。检测CD4+CXCR5+Tfh水平不仅对判断感染者的免疫状态有重要意义，也可为肺炎克雷伯菌感染者治疗提供依据。     

Comparison of in vitro activity of ertapenem with other carbapenems against extended-spectrum beta-lactamase-producing Escherichia coli and Kleibsella species isolated in a tertiary children's hospital

Objective: The purpose of this study was to evaluate the susceptibility of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae clinical isolates to ertapenem in a tertiary pediatric care center in Turkey.

Design/methods: All isolates of ESBL-producing Enterobacteriaceae were collected from clinical specimens from children, and susceptibility tests were done using the Vitek 2 compact system.

Results: Ninety-nine per cent of the ESBL-producing Escherichia coli isolates were found to be susceptible to ertapenem, 99.5% to imipenem and 100% to meropenem. In the Klebsiella species, 91.5% of the isolates were susceptible to ertapenem, 99.3% to imipenem and 100% to meropenem.

Conclusion: The results of our data, including isolates from children, showed that ertapenem had high in vitro activity against the majority of the ESBL-producing E. coli and Klebsiella species, as reported in previously published studies. However, additional clinical studies are required to assess the clinical activity of ertapenem and the clinical importance of the resistant isolates.     

Chlamydia pneumoniae and Atherosclerosis

Chlamydia pneumoniae, a human respiratory pathogen, has been linked to atherosclerotic disease based on sero-epidemiologic studies, direct detection of the organism in atherosclerotic lesions, animal experiments and tissue culture. In this review paper we propose to interprete results in line with the biology of Chlamydia with persistence of Chlamydia pneumoniae antigens in the pathogenesis of atherosclerosis rather than viable bacteriae.     

儿童肺炎支原体肺炎的诊疗进展

儿童肺炎支原体肺炎（MPP）在儿童呼吸道感染中所占比例日趋增多，肺炎支原体的耐药率也日趋增加。MPP的发病机制尚不十分明确，其临床表现除呼吸系统本身症状以外常可累及消化、血液、神经、心血管、泌尿等其他多个系统。对于MPP的治疗目前主要为大环内酯类抗生素、免疫治疗、中西医结合治疗及对症治疗等。本文将对儿童MPP的诊疗进展做一综述。     

Differentiation between Streptococcus pneumoniae and other viridans group streptococci by matrix-assisted laser desorption/ionization time of flight mass spectrometry

ObjectivesMatrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is becoming the method of choice for bacterial identification. However, correct identification by MALDI-TOF of closely related microorganisms such as viridans streptococci is still cumbersome, especially in the identification of S. pneumoniae. By making use of additional spectra peaks for S. pneumoniae and other viridans group streptococci (VGS). We re-identified viridans streptococci that had been identified and characterized by molecular and phenotypic techniques by MALDI-TOF.MethodsVGS isolates (n = 579), 496 S. pneumoniae and 83 non-S. pneumoniae were analysed using MALDI-TOF MS and the sensitivity and specificity of MALDI-TOF MS was assessed. Hereafter, mass spectra analysis was performed. Presumptive identification of proteins represented by discriminatory peaks was performed by molecular weight matching and the corresponding nucleotides sequences against different protein databases.ResultsUsing the Bruker reference library, 495 of 496 S. pneumoniae isolates were identified as S. pneumoniae and one isolate was identified as non-S. pneumoniae. Of the 83 non-S. pneumoniae isolates, 37 were correctly identified as non-S. pneumoniae, and 46 isolates as S. pneumoniae. The sensitivity of the MALDI-TOF MS was 99.8% (95% confidence interval (CI) 98.9–100) and the specificity was 44.6% (95% CI 33.7–55.9). Eight spectra peaks were mostly present in one category (S. pneumoniae or other VGS) and absent in the other category and inversely. Two spectra peaks of these (m/z 3420 and 3436) were selected by logistic regression to generate three identification profiles. These profiles could differentiate between S. pneumoniae and other VGS with high sensitivity and specificity (99.4% and 98.8%, respectively).ConclusionsSpectral peaks analysis based identification is a powerful tool to differentiate S. pneumoniae from other VGS species with high specificity and sensitivity and is a useful method for pneumococcal identification in carriage studies. More research is needed to further confirm our findings. Extrapolation of these results to clinical strains need to be deeply investigated.     

2010~2012年913株肺炎克雷伯菌感染的分布与耐药性研究

目的调查肺炎克雷伯菌的分布及其耐药性变化。方法选择2010年1月至2012年12北京市肿瘤防治研究所收集的913株肺炎克雷伯菌临床分离菌株作为研究对象,采用K-B法进行药敏试验,所得数据采用WHONET 5.6进行分析。结果肺炎克雷伯菌临床分离菌株的标本主要来源于痰标本(46.0%);超广谱β-内酰胺酶(ESBLs)阳性菌株的阳性率为51.2%;连续3年的药敏结果显示,肺炎克雷伯菌对哌拉西林、头孢呋辛、头孢噻肟、氨苄西林/舒巴坦、复方磺胺甲口恶唑和环丙沙星有较高的耐药率(>30%)。结论近3年来,肺炎克雷伯菌所致感染的耐药率趋于平稳,但肺炎克雷伯菌ESBLs阳性率较高。     

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??Objective To compare pbp2b??ply and lytA genes PCR with cerebral spinal fluid culture in diagnosis of Streptococcus pneumoniae meningitis and prediction of its susceptibility. Methods A nested PCR targeting pbp2b and another two S.pneumoniae specific PCR targeting the genes of pneumolysin??ply?? and autolysin??lytA?? were developed for detection of S.pneumoniae in cerebral spinal fluid from bacterial meningitis patients. The three PCR results and culture were compared. The consistency of penicillin susceptibility PCR ??using resistant and susceptible primers respectively????sequencing and culture-based phenotypic penicillin resistant results were compared. Results Of the 161 specimens studied??there were 25 cases of S.pneumoniae infection confirmed by different methods??16 by pbp2b PCR??16 by lytA PCR??14 by ply PCR and 9 by cerebrospinal fluid culture??. Of the 16 pbp2b positive specimens??penicillin sensitive and resistant sequence types accounted for half??respectively. Four of the 16 pbp2b positive specimens had culture-based phenotypic penicillin-resistant result. Three of 4 were consistent with penicillin susceptibility PCR result. The results of susceptibility PCR targeting pbp2b was consistent with sequencing result. New sequence types were found but there were no new point mutations in these strains when compared with GenBank ??http??//blast.ncbi.nlm.nih.gov/Blast.cgi??. Penicillin resistance in pneumococcal meningitis was 66.67%??6/9?? by culture phenotype and 50%??8/16?? by PCR and sequencing when culture was negative. Conclusion Pbp2b can serve as a good target gene to detect S.pneumoniae and predict its penicillin susceptibility??which is especially important when culture is negative.